1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof.
2. Description of Related Art
In a semiconductor device having a transistor, isolating an element formation region using an isolation region is commonly practiced. The gate electrode of the transistor is formed so as to pass over the element formation region, and also extends over the isolation region adjacent to the element formation region (see, e.g., International Publication WO 2007/072537 Pamphlet). In a semiconductor device disclosed in International Publication WO 2007/072537 Pamphlet, the upper surface of the element formation region and the upper surface of the isolation region are located in the same plane.